Malthus’ ideas haven’t quite been discredited but his alarmism certainly has. As world population increases from the current 6 billion and approaches around 9 to 10 billion by 2100 studies suggest that population growth can have economic and environmental benefits.
A new article in Science 29 July 2011: Vol. 333 no. 6042 pp. 544-546
Are More People Necessarily a Problem?
by David Malakoff
In 1937, A bureaucrat serving in the British Empire’s Kenya Colony penned an alarming memo to his bosses about conditions in the Machakos Reserve, a hilly, drought-prone farming region 50 kilo meters south of Nairobi. “Benevolent British rule” had encouraged the explosive “multiplication” of the “natives,” he reported, leading to massive environmental degradation. “Every phase of misuse of land is vividly and poignantly displayed in this Reserve, the inhabitants of which are rapidly drifting to a state of hopeless and miserable poverty and their land to a parching desert of rocks, stones and sand.” The apocalyptic warning came as the region’s population approached 250,000.
Today, more than 1.5 million people call Machakos home. Rather than a cautionary example of the perils of overpopulation, however, for some experts Machakos has become a symbol of something very different: the idea that rapid human population growth, even in some of Earth’s driest, most challenging environments, is not necessarily a recipe for disaster—and can even bring benefits. They argue that, over the past 75 years, population growth in Machakos and nearby Nairobi has triggered social and economic shifts that have made it possible for residents to regreen once-barren hillsides, reinvigorate failing soils, reduce birth rates, and increase crop production and incomes. “A landscape that was once declared good for nothing is now like a garden when the rain falls,” says Michael Mortimore, a geographer with Drylands Research, a United Kingdom–based nonprofit organization, who helped document the turnaround in More People, Less Erosion, a 1994 study that is still influential—and controversial—today. “Too many people still have the simplistic notion that too many people is a problem,” he says. “What happened in Machakos challenges that pessimism.”…..
……. Many see crisis looming in those numbers for people and the environment. Others, however, see some hope for a transition to more sustainable livelihoods and cite Ester Boserup, a Danish economist who died in 1999, as one source of their optimism. In 1965, the then-little-known Boserup, who spent most of her career consulting for international development institutions, published a slim volume titled The Conditions of Agricultural Growth: The Economics of Agrarian Change under Population Pressure. (pdf Boserup1965) It examined the history of subsistence farming and offered a theory that essentially turned Malthus upside down. Instead of rising population density leading to barren fields and starvation, Boserup suggested it could naturally trigger “intensification”: the use of new technologies and more labor to get bigger harvests from less land.
“The idea was that people weren’t just mouths to feed but also brains that could think and hands and legs that could work very hard”.
….. In some parts of Africa, meanwhile, researchers are documenting a notable, Machakos-like “regreening” of arid areas with fast-growing populations. …. There’s some evidence that the extra greenery is helping to make poor farm communities more resilient to droughts and economic setbacks, but the long-term outlook remains at best unclear.
In the forest frontiers of South and Central America, researchers have found both Malthusian and Boserupian forces at work in deforestation. Depending on local circumstances, families faced with growing population densities have responded by both migrating to clear new farms in forested areas, the agricultural “extensification” predicted by Malthus, and intensified land use à la Boserup, a team led by David Carr of the University of California, Santa Barbara, reported in a 2009 study in Population and Development. Paradoxically, the result is that areas with relatively low population densities can have much higher deforestation rates than those with higher densities.
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Sustainable growth in Machakos by Francis Gichuki , Mary Tiffen , Michael Mortimore, ILEIA Newsletter • 9 nº 4 • December 1993
More People, Less Erosion, Overseas Development Institute UK, 1994